These come in smaller capacities as well. There are two available models - one with G-Force protection and one without. I got the one with G-Force accidentally without paying more for it:

ST9320421ASG (models without G-Force lack the G at the end)

For those wondering about prices, the lowest price on the 320GB model is $170 plus tax right now which can be found at NCIX and some smaller Toronto Chinatown stores. I got mine for $139.99 + tax at Filtech. They had to back-order it but the 4 day wait was well worth the $30 in savings for me.

So here are the HD Tune graphs:

100GB Seagate Momentus 7200.1 PATA 8MB Cache

120GB Seagate Momentus 7200.2 SATA 8MB Cache

320GB Seagate Momentus 7200.3 SATA 16MB Cache G-Force

As you can see, between the 7200.1 and 7200.2 generations, there is already a massive difference. But the 7200.3 scores were simply amazing!

Here's a graph from one of my 500GB Western Digital SATA 7200rpm 16MB Cache HDs (WD5000AAKS). We can see here that save for the burst rate, transfer rates are identical. With the 7200.3, one can have true 7200rpm desktop performance in a laptop finally!